The present invention relates to the treatment of cancer with a parenteral nutritional supplement, particularly a supplement having a specific class of structured lipids as its primary fat source. Surprisingly, the supplement containing these structured lipids, when used as part of a total parenteral nutrition diet, has been shown to modify tumor growth rate, tumor fractional synthetic rate, and tumor protein breakdown rate. As indicated by the previously cited U.S. Pat. No. 4,906,664, the same structured lipids are also useful in the treatment of cancer cachexia, the fasting-like state associated with certain forms of cancer.
Total parenteral nutrition, as well as parenteral nutritional supplements, are often used in the treatment of critically ill patents to provide necessary fats and other calorie sources required for survival of the patient. Heretofore, these supplements have been considered useful solely to ameliorate the physiologic loss of nutrients in patients such as those having undergone surgery or cancer therapy. Although certain medium-chain triglycerides and structured lipids, including some containing medium-chain triglycerides, have been shown to have benefits in treating hypercatabolic patients, see U.S. Pat. No. 4,528,197, assigned to KabiVitrum, Inc.; DeMichele et al., "Effective Total Enteral Nutrition with Structured Lipids on Protein Metabolism in Thermally Injured Rats," Fed.Proc. 46:1086 (1987); Bach and Babayan, "Medium-Chain Triglycerides: Update," Am.J.Clin.Nutrition 36:950-962 (November 1982); and U.S. Pat. No. 4,703,062, assigned to Baxter-Travenol, Inc., no work was published describing the effects of using structured lipids as a cancer cachexia treatment before the filing of the aforementioned U.S. Pat. No. 4,906,664.
While some of the work described in these papers concerned the effects of medium-chain triglycerides and structured lipids on ill or stressed patients, there was nothing to suggest that a change in the fat content of the diet could actually affect cancerous tumor growth rates and/or protein metabolism in the tumors. Even the early work on the family of structured lipids used in the present invention, see U.S. Pat. No. 4,871,768, gave no indication of the beneficial effects of this family of structured lipids in cancer treatment. In fact, early tests to determine if a change in nutritional lipids can affect a cancer treatment, Crosby et al., "Effect of Structured Lipid-Enriched Total Parenteral Nutrition in Rats Bearing Yoshida Sarcoma," J.Nutritional Biochemistry (In Press) indicated that there was no improvement in terms of tumor growth rate or fractional synthetic rate by a modification in the parenteral diet from classic long-chain triglyceride (LCT) mixtures of soybean oil and safflower oil to the structured lipids. However, this early work was carried out using structured lipids having medium-chain and long-chain .omega.6 fatty acids, not .omega.3 fatty acids. In contrast, the present invention requires that as a statistical average, both the medium-chain fatty acids and the .omega.3 fatty acid be on the same structured lipid.
Until the experiments which lead to the present invention was carried out, even those involved in the test program did not believe that the structured lipids would have any effect on cancer. A 1986 article by one of the inventors, Bistrian, "Some Practical and Theoretical Concepts in Nutritional Assessment of the Cancer Patient," CANCER 58(8):1863-1866 (1986) did not even theorize that a change in parenteral nutrition could modify tumor growth rate but rather merely suggested that there was some parallel between hypercatabolic states and cancer cachexia, the fasting-like state often associated with cancer. There was no inkling whatsoever that diet modification could reduce the tumor growth rate or otherwise affect the cancer itself as compared with the cachectic state associated with it.
Accordingly, an object of the invention is to provide a lipid-based diet or nutritional support which can treat cancer.
Another object of the invention is to provide a nutrition supplement which can affect cancer tumor growth rate.
A further object of the invention is to provide total parenteral nutrition for the treatment of cancer.
These and other objects and features of the invention will be apparent from the following description.